/*!	 trgt_gif.h
**	 Template Header
**
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
** === N O T E S ===========================================================
**
** ========================================================================= */

#ifndef __SYNFIG_TRGT_GIF_H
#define __SYNFIG_TRGT_GIF_H

#include <synfig/target_scanline.h>
#include <synfig/string.h>
#include <synfig/smartfile.h>
#include <cstdio>
#include <synfig/surface.h>
#include <synfig/palette.h>
#include <synfig/targetparam.h>

class gif : public synfig::Target_Scanline
{
    SYNFIG_TARGET_MODULE_EXT
private:
    // Class for abstracting the
    // output of the codes
    struct bitstream {
        synfig::SmartFILE file;
        unsigned char pool;
        char curr_bit;
        bitstream(): pool(0), curr_bit(0), curr_pos(0) {}
        bitstream(synfig::SmartFILE file): file(file), pool(0), curr_bit(0), curr_pos(0) {}
        unsigned char buffer[256];
        int curr_pos;

        // Pushes a single bit onto the bit
        void push_bit(bool bit)
        {
            if (bit) {
                pool |= (1 << (curr_bit));
            }

            curr_bit++;

            if (curr_bit == 8) {
                empty();
            }
        }

        // Empties out the current pool into
        // the buffer. Calls 'dump()' if the
        // buffer is full.
        void empty()
        {
            buffer[curr_pos++] = pool;
            curr_bit = 0;
            pool = 0;

            if (curr_pos == 255) {
                dump();
            }
        }

        // If there is anything in the
        // buffer or in the pool, it
        // dumps it to the filestream.
        // Buffer and pool are cleared.
        void dump()
        {
            if (curr_bit) {
                empty();
            }

            if (curr_pos || curr_bit) {
                fputc(curr_pos, file.get());
                fwrite(buffer, curr_pos, 1, file.get());
                curr_pos = 0;
            }
        }

        // Pushes a symbol of the given size
        // onto the bitstream.
        void push_value(int value, int size)
        {
            int i;

            for (i = 0; i < size; i++) {
                push_bit((value >> (i)) & 1);
            }
        }
    };

    // Class for dealing with the LZW codes
    struct lzwcode {
        int value; // the data element or character
        int code; // lzwcode
        struct lzwcode* kids; // children of this node
        struct lzwcode* next; // siblings of this node

        lzwcode(): value(0), code(0), kids(0), next(0) { }

        lzwcode *FindCode(int value)
        {
            lzwcode *node = this;

            // check the children (kids) of the node for the value
            for (node = node->kids; node != 0; node = node->next)
                if (node->value == value) {
                    return (node);
                }

            return (0);
        }

        void AddNode(unsigned short code, unsigned short value)
        {
            lzwcode *n = new lzwcode;

            // add a new child to node; the child will have code and value
            n->value = value;
            n->code = code;
            n->kids = 0;
            n->next = this->kids;
            this->kids = n;
        }

        static lzwcode * NewTable(int values)
        {
            int i;
            lzwcode * table = new lzwcode;

            table->kids = 0;

            for (i = 0; i < values; i++) {
                table->AddNode(i, i);
            }

            return (table);
        }

        // Destructor just deletes any
        // children and siblings.
        ~lzwcode()
        {
            if (kids) {
                delete kids;
            }

            if (next) {
                delete next;
            }
        }
    };

private:
    bitstream bs;
    synfig::String filename;
    synfig::SmartFILE file;
    int
    i,			// General-purpose index
    codesize,	// Current code size
    rootsize,	// Size of pixel bits (will be recalculated)
    nextcode;	// Next code to use
    lzwcode *table, *next, *node;

    synfig::Surface curr_surface;
    etl::surface<unsigned char> curr_frame;
    etl::surface<unsigned char> prev_frame;

    int imagecount;
    int cur_scanline;

    // GIF compression parameters
    bool lossy;
    bool multi_image;
    bool dithering;
    int color_bits;
    int iframe_density;
    int loop_count;
    bool local_palette;

    synfig::Palette curr_palette;

    void output_curr_palette();

public:
    gif(const char *filename, const synfig::TargetParam& /* params */);

    virtual bool set_rend_desc(synfig::RendDesc *desc);
    virtual bool init(synfig::ProgressCallback *cb);
    virtual bool start_frame(synfig::ProgressCallback *cb);
    virtual void end_frame();

    virtual ~gif();

    virtual synfig::Color * start_scanline(int scanline);
    virtual bool end_scanline(void);

};

#endif